Thanks very much Peter, Marc, Suavi and beren :-)
What's everyone's thoughts on the colour? It's interesting to compare this one with Mike and Peter's recent efforts. I'd like to point out that the point of this post is not to cause argument about which of these images is better, it's just interesting to compare the different approaches/results.
Mike's one is reasonably neutral in colour, Peter's looks a bit more blue. Mine clearly has a lot more red than either of those.
Truth be told, I prefer the more neutral / blue colour in terms of aesthetics and I've produced images in the past that have been more like that.
The image in my original post used PhotometricColorCalibration in PixInsight with default white reference. From there, I did drop the red a touch, but as you can see in my image, it's still a lot more red than is often shown.
Note that Vincent Peres and Juan Conejero claim the default white reference used in PCC is the "best unbiased white reference, truly representative of the observed deep sky"
I did some cursory reading... typically I'm just a "pretty picture" astrophotographer, I have little to no understanding of the science, so I could be wrong here and I'd appreciate correction if I am.
My understanding is that the exact classification of Cen A is subject to debate, but it's considered to be either an elliptical, or a lenticular galaxy. My understanding is that both of those galaxy types tend to be populated mostly by older, red stars.
I found
this abstract which seems to confirm that: "bulk of the stars with ages in excess of ~10 Gyr"
So based on this, I'm of the understanding that Cen A is probably a bit more red than is often shown... but frankly I don't think it looks as nice that way ;-)
Attached is a quick process using a non-standard white reference, specifically that of an elliptical galaxy. It has a lot more blue and looks closer to Mike and Peter's images in terms of colour... I personally think it looks better than my initial version. Maybe this could be considered more correct in colour from the perspective of a viewer
within Cen A?
Something else to consider: how much do we actually
care about the truth of the colour, whatever that is?